Rebuild in progress - can't turn crank?

[60-66]

All bearings need to be put in dry during assembly, I always cleaned with lacquer thinner before putting them in. They will get oil behind them to prevent rust on there own , have never seen rust behind a bearing on a rebuilt good running engine so I wouldn't worry about that. Ive seen engines assembled that guys couldn't move the crank where oil was put on the block and back of bearing during assembly. We ALWAYS measured the bearings in the block like PGSIGNS outlined above, then ground the crank to fit .I was a crankshaft grinder for 20plus years. .0003 or three tenths on the low end is guaranteed to fail as they're showing in that manual , even .001 will fail eventually. I would be at the high end minimum for main clearance but as I've said I still "like" .002-.0025 IMHO . GM on an assembly line to gain clearance or reduce clearance had a wide range of over and under bearings even for a standard ground crankshaft. I can pretty much guarantee GM never assembled an engine with .0003 to .001 clearances

[60-66]

To the comment above on the "bent crank" yes that's a great thing to check and is very important. However , just knocking a crank over isn't going to bend it if it was perfectly straight out of the machine. Would take a pretty good hit to bend it.

One other area that will cause the crank to not rotate is the radius of the journal , if the bearing comes in contact with the radius it wont move , look for shinny spots on the edge of the bearing and also tap the crank back and forth before torqueing the thrust bearing. The tapping of the crank like that aligns the bearing to the thrust surface of the crankshaft. That's your "end play"

[mongocanfly]

If you want to check the crank run out ,remove all the bearings and caps from the center section of the crank...leaving the ends installed and torqued...put a dial indicator on the center main jornal and spin the crank...if the crank is warped thatll show it..
When you got the new block was it a assembled engine that you tore down...or just a bare block...someone could have mixed up the caps...

[Praxiss454]

Originally Posted by mongocanfly

If you want to check the crank run out ,remove all the bearings and caps from the center section of the crank...leaving the ends installed and torqued...put a dial indicator on the center main jornal and spin the crank...if the crank is warped thatll show it..
When you got the new block was it a assembled engine that you tore down...or just a bare block...someone could have mixed up the caps...

Bare block. The machinist said he stamped them before he took the caps off to bore the cylinders, but its possible the caps were previously mixed up. He suggested I swap the two that seemed tight (2 and 6) but it still wouldn't turn. They said they'd get to look at it today so I'm just waiting for a call back.

[Praxiss454]

Okay, it turns out the problem was two fold.
1. The caps were in the wrong order on the block when we received it. When putting them into the proper order, they were still a bit tight.
2. The shop measured everything and decided to align-hone (no charge to me), and now it spins like butter.

Thanks for the help.

[mongocanfly]

Good deal..when you started removing caps 1by1 and it spun,that kinda told that something was wrong with the cap setup
We're the caps numbered correct and in the wrong order or stamped wrong?

[Praxiss454]

Originally Posted by mongocanfly

Good deal..when you started removing caps 1by1 and it spun,that kinda told that something was wrong with the cap setup
We're the caps numbered correct and in the wrong order or stamped wrong?

This was a replacement used block we found locally because my original block had a few cracks. When we received the block, we stamped the caps in their existing order without testing/measuring them. When reassembling, we found it tight and discovered they were not in the right order.

[mattfranklin]

Originally Posted by Praxiss454

This was a replacement used block we found locally because my original block had a few cracks. When we received the block, we stamped the caps in their existing order without testing/measuring them. When reassembling, we found it tight and discovered they were not in the right order.

Wow, that's an interesting one. Glad you got to the bottom of it. I was getting stressed just reading the thread.

[Myself]

A buddy of mine had this problem with a Ford he was building. I went over to check it out and found only one rod cap causing the bind. Swapped with another rod and te binding followed the rod. Good used rod from another local Ford guy and we were back on track. It had an ever so slight bend to it.